/*
 * Created on 22 Jun 2006
 * Created by Paul Gardner
 * Copyright (C) Azureus Software, Inc, All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 */

package com.aelitis.azureus.core.networkmanager.impl.udp;

import org.gudy.azureus2.core3.config.COConfigurationManager;
import org.gudy.azureus2.core3.config.ParameterListener;
import org.gudy.azureus2.core3.logging.LogAlert;
import org.gudy.azureus2.core3.logging.Logger;
import org.gudy.azureus2.core3.util.Constants;
import org.gudy.azureus2.core3.util.Debug;
import org.gudy.azureus2.core3.util.RandomUtils;

import com.aelitis.azureus.core.networkmanager.impl.ProtocolDecoderPHE;
import com.aelitis.net.udp.uc.PRUDPPacket;

public class UDPNetworkManager {
    public static final boolean MINIMISE_OVERHEADS = true;

    public static final int MIN_INCOMING_INITIAL_PACKET_SIZE = ProtocolDecoderPHE.MIN_INCOMING_INITIAL_PACKET_SIZE;
    public static final int MAX_INCOMING_INITIAL_PACKET_SIZE = ProtocolDecoderPHE.getMaxIncomingInitialPacketSize(MINIMISE_OVERHEADS);

    private static final int MIN_MSS = 128;
    private static final int MAX_MSS = PRUDPPacket.MAX_PACKET_SIZE;

    private static int udp_mss_size;

    public static boolean UDP_INCOMING_ENABLED;
    public static boolean UDP_OUTGOING_ENABLED;

    static {
        COConfigurationManager.addAndFireParameterListener("UDP.Listen.Port.Enable", new ParameterListener() {
            public void parameterChanged(String name) {
                UDP_INCOMING_ENABLED = UDP_OUTGOING_ENABLED = COConfigurationManager.getBooleanParameter(name);
            }
        });
    }

    public static int getUdpMssSize() {
        return udp_mss_size;
    }

    public static void refreshRates(int min_rate) {
        udp_mss_size = COConfigurationManager.getIntParameter("network.udp.mtu.size") - 40;

        if (udp_mss_size > min_rate)
            udp_mss_size = min_rate - 1;

        if (udp_mss_size < MIN_MSS)
            udp_mss_size = MIN_MSS;

        if (udp_mss_size > MAX_MSS)
            udp_mss_size = MAX_MSS;
    }

    private static UDPNetworkManager singleton;

    public static UDPNetworkManager getSingleton() {
        synchronized (UDPNetworkManager.class) {

            if (singleton == null) {

                singleton = new UDPNetworkManager();
            }
        }

        return (singleton);
    }

    private int udp_listen_port = -1;
    private int udp_non_data_listen_port = -1;

    private UDPConnectionManager _connection_manager;

    protected UDPNetworkManager() {
        COConfigurationManager.addAndFireParameterListener("UDP.Listen.Port", new ParameterListener() {
            public void parameterChanged(String name) {
                int port = COConfigurationManager.getIntParameter(name);

                if (port == udp_listen_port) {

                    return;
                }

                if (port < 0 || port > 65535 || port == Constants.INSTANCE_PORT) {

                    String msg = "Invalid incoming UDP listen port configured, " + port + ". The port has been reset. Please check your config!";

                    Debug.out(msg);

                    Logger.log(new LogAlert(LogAlert.UNREPEATABLE, LogAlert.AT_ERROR, msg));

                    udp_listen_port = RandomUtils.generateRandomNetworkListenPort();

                    COConfigurationManager.setParameter(name, udp_listen_port);

                } else {

                    udp_listen_port = port;
                }
            }
        });

        COConfigurationManager.addAndFireParameterListener("UDP.NonData.Listen.Port", new ParameterListener() {
            public void parameterChanged(String name) {
                int port = COConfigurationManager.getIntParameter(name);

                if (port == udp_non_data_listen_port) {

                    return;
                }

                if (port < 0 || port > 65535 || port == Constants.INSTANCE_PORT) {

                    String msg =
                            "Invalid incoming UDP non-data listen port configured, " + port
                                    + ". The port has been reset. Please check your config!";

                    Debug.out(msg);

                    Logger.log(new LogAlert(LogAlert.UNREPEATABLE, LogAlert.AT_ERROR, msg));

                    udp_non_data_listen_port = RandomUtils.generateRandomNetworkListenPort();

                    COConfigurationManager.setParameter(name, udp_non_data_listen_port);

                } else {

                    udp_non_data_listen_port = port;
                }
            }
        });
    }

    public boolean isUDPListenerEnabled() {
        return (UDP_INCOMING_ENABLED);
    }

    public int getUDPListeningPortNumber() {
        return (udp_listen_port);
    }

    public boolean isUDPNonDataListenerEnabled() {
        return (UDP_INCOMING_ENABLED);
    }

    public int getUDPNonDataListeningPortNumber() {
        return (udp_non_data_listen_port);
    }

    public UDPConnectionManager getConnectionManager() {
        synchronized (this) {

            if (_connection_manager == null) {

                _connection_manager = new UDPConnectionManager();
            }
        }

        return (_connection_manager);
    }
}
